I recently bought a house in Kelowna and the entire property has a cedar hedge privacy fence around it. They are about 3-4' wide and 10-12' tall. All of them have decent growth on the tops & the sides and for the most part are a very nice vibrant green. However there are some spots around all of them that vary in size from a foot or so in diameter to 4-5 feet where they are browning from the tips. We irrigate every second day for 40 minutes and I have fertilized them once with a 30-10-10, spraying the entire hedges with a garden hose fertilizer. I really want to keep these hedges healthy, what can I do?